If people move about in a room fitted with rigid floor panels, the noise development is clearly greater than in rooms fitted with carpets or elastic floor coverings such as PVC. The noise development is based on reflections of shock waves introduced into the floor when it is walked on. The amplitude spectrum of the shock or sound waves depends on the room-floor, floor-substrate boundaries and on the attenuation in the different layers. The noise development is particularly high if a layer of air remains between two layers, i.e. for example between the laminate floor and the screed below it.
In order to reduce the noise development from walking, various mat-like materials, such as closed-cell polyethylene foam, cork, polymer-bonded mats of recycled rubber and cork, corrugated card or soft wood-fibre fabrics are used as an underlay under a rigid floor covering above the screed. The sound-absorbing effect that can be achieved by this method is unsatisfactory, however.
Attempts have therefore already been made to stick the above mat-like materials directly to the back of a rigid floor covering, i.e. on the base of a floor panel, for example. Disadvantageously, this involves high technical complexity. The costs are consequently high. Overall, the sound reduction is unsatisfactory in relation to the technical complexity.
From the document DE 196 20 987 C1, for example, an insulating film is known, which is equipped with an adhesive strip. It is intended to stick the insulating film on to the bottom of a rigid floor covering so as to reduce noise development when the floor is walked on.
From the document DE 43 29 766 A1, it is known to provide a polymer material for the footstep sound insulation of a floor.
According to the document DE 38 35 638 A1 an insulating material made of expandable polystyrene is used as an insulating layer in rigid floor coverings.